The present invention relates to protection against the propagation of fire between zones separated by a wall and between which free exchange of air must be produced in normal situations and more particularly relates to a fire barrier device which can be mounted in the separating wall of the aforementioned zones.
Fire barrier protections in particular for electrical power cables are ensured by means of fire barrier sheaths made of leaktight products.
Such cables release by the Joule effect a quantity of heat which causes heating in their bulk.
The temperature reached by a cable after stabilisation is linked to the efficiency of the fire barrier protective sheath.
It is therefore necessary to produce a fire barrier device which, while ensuring in the case of fire the required protection, that is to say a fire barrier function for a predetermined period of time, allows in normal operating conditions dissipation of the heat released by the Joule effect which is sufficient to guarantee correct behaviour of the protected cables over time.
The ventilation of electrical power cables inside their protective jacket or sheath has hitherto been ensured either by a dynamics system called a "strap-type shutter", or by a protection device provided with an opening which is not blockable in the case of outbreak of fire.
The strap-type shutter has the following drawbacks:
The complexity of its construction requires it to be produced partly in a unitary manner, to requirements, on site; PA1 it is subject to risks of premature closure by mechanical breaking of the strap with a heat-meltable fuse when the protected cables are in use; PA1 it is difficult to reopen after the fire; PA1 it is difficult to fit with precision with respect to surrounding equipment because of its large bulk caused by the presence of the strap and of a cover which is to be held open under normal operating conditions.